I do 3 things to keep my goggles super doper. I clean it with the provided synthetic cloth, which in time, will wear off the anti-fog. So #2, I bought an anti-fog spray which works amazing. And #3, I put rain-x on the outside of the lenses to bead any precipitation. yup, but use the provided cloth.
just make sure eberything is dry. if its dry you wont hurt the antifog.